JPH07217616A - Clamping screw - Google Patents

Abstract

PURPOSE:To provide a clamping screw having structure which is formed in such a way that rotating force of a clamping screw main body is not transmitted to a ball. CONSTITUTION:A ball storing part 2 is provided on the top end of a clamping screw main body 1. In the ball storing part 2, a supporting ball 3 consisting a supporting means is free rotatably storing-arranged on a back side, and a contact ball 4 is also free rotatably storing-arranged on an opening side. The screw surface 1a of the clamping screw main body 1 is screwed in a clamping screw supporting tool, it is rotated, and work is fastened and fixed. At this time, since the contact ball 4 is supported at a point X by the supporting ball 3, the contact ball 4 is not interlockingly rotated by rotation of the clamping screw main body 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clamping screw used for fixing a work on a table of a machine tool, for example.

[0002]

2. Description of the Related Art Conventionally, as this type, there is one as shown in FIG. That is, a conical hole-shaped ball accommodating portion 22 is formed at the tip of the clamping screw main body 21 having the screw surface 21a on the outer peripheral surface. A spherical ball 23 is housed in the ball housing portion 22.

When the work is fixed by the clamping screw having the above structure, although not shown, the screw surface of the clamping screw main body 21 is attached to the screw surface of the clamping screw support provided near the table on which the work is placed. 21a is screwed together. Then, by rotating the work placed on the table, the clamping screw is moved in the work direction based on the action of the screw, and the ball 23 is pressed and fixed to the work. When the clamping force against the work is not strong, there is almost no contact resistance between the ball 23 and the inner bottom surface 22b of the ball accommodating portion 22 due to the rotation of the clamping screw. Therefore, the clamping screw body 21 can be smoothly rotated.

The ball accommodating portion 22 is not limited to the conical hole shape as described above, but has a spherical shape as shown in FIG.

[0005]

However, when the clamping screw main body 21 is further rotated and the work is tightly tightened, the contact resistance between the ball 23 and the inner bottom surface 22b of the ball accommodating portion 22 increases, and the clamping force is increased. The ping screw body 21 cannot be rotated smoothly.

Further, due to the contact resistance between the ball 23 and the inner bottom surface 22b of the ball accommodating portion 22, the ball 23 starts rotating in conjunction with the clamping screw body 21. As a result, the rotational force of the clamping screw main body 21 is transmitted to the work through the ball 23, the work is rotated in conjunction with each other, and the position of the work may deviate from a predetermined position. At this time, since the work is firmly clamped by the clamping screw, in order to return the work to the predetermined mounting position, it is necessary to loosen the clamping screw and place it again, which is troublesome. Was hanging.

The present invention has been made in view of the problems existing in the above-mentioned prior art, and an object thereof is to provide a clamping screw having a structure in which the rotational force of the clamping screw body is not transmitted to the balls. Especially.

[0008]

In order to achieve the above object, according to the present invention, a clamping screw main body having a ball receiving portion at its tip and a ball screwing portion which is rotatably accommodated in the ball receiving portion, and A part of the ball is projected from the ball accommodating portion, and a support means provided in the ball accommodating portion and supporting the ball at one point on the rotation axis of the clamping screw body.

Further, according to the present invention, the supporting means is a curved surface formed so as to face the ball. Further, in the present invention, the supporting means is a convex portion formed facing the ball.

Moreover, in the present invention, the supporting means is a supporting ball housed and arranged between the inner part of the ball housing portion and the ball.

[0011]

[Effect] Even if the clamping screw having the above-mentioned structure is firmly tightened to the work, the ball is supported by the supporting means arranged in the ball accommodating portion at the point,
The rotational force of the clamping screw body is not transmitted to the ball. Therefore, the clamping screw main body can be smoothly rotated, and the work does not rotate in association with the rotation of the clamping screw main body, and is not displaced from that position.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the clamp pin screw of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the clamping screw main body 1 is made of a stainless material in the shape of a round bar. This clamping screw is provided on the outer peripheral surface of the clamping screw main body 1 in the vicinity of a work such as a machine tool. A clamping screw support 11 (shown in FIG. 3).
A screw surface 1a for screwing into is formed. Also,
Wrench hole 1 at the base end of clamping screw body 1
b is provided so that the clamping screw can be rotated by a hexagon wrench. A ball accommodating portion 2 is recessed at the tip of the clamping screw body 1. The ball accommodating portion 2 is formed in a conical shape.

As shown in FIGS. 1 and 2, a support ball 3 as a support means is provided in the inner portion of the ball accommodating portion 2, and a contact ball 4 made of a stainless material is provided on the opening side of the ball accommodating portion 2. Each is housed. The contact ball 4 is supported by the support ball 3 in a substantially point contact state. A part of the contact ball 4 projects from the opening 2a. The opening 2a of the ball housing portion 2 is slightly narrowed to prevent the contact ball 4 from falling off.

Next, the operation of the clamping screw of this embodiment will be described. As shown in FIG. 3, a machine tool (not shown) is provided with a table 10 on which a work W is placed. A pair of clamping screw supports 11 are provided on both sides of the table 10, and their screw surfaces 12
The screw surface 1a of the clamping screw body 1 is screwed onto the. Then, with the work W placed on the table 10, a wrench is inserted into the wrench hole 1b (shown in FIG. 1) and rotated to move the clamping screw in the work W direction, so that one point of the contact ball 4 is moved. Contact the work W and tighten from both sides.

When the clamping screw body 1 is further rotated to firmly tighten the work W, the contact resistance at the contact line T between the support ball 3 and the inner bottom surface 2b of the ball accommodating portion 2 increases. However, since the support ball 3 and the contact ball 4 are in contact with each other at a point X on the rotation axis L of the clamping screw body 1, even if the support ball 3 rotates together with the clamping screw body 1, the rotation of the support ball 3 is prevented. The contact ball 4 is not rotated in conjunction therewith.

As described above, according to the clamping screw of this embodiment, even if the work W is firmly tightened, the rotational force of the clamping screw body 1 is not transmitted to the contact balls 4. Therefore, the clamping screw body 1 can be always smoothly rotated, and the contact point S between the contact ball 4 and the work W is not rubbed and scratched. Moreover, since the rotational force of the clamping screw body 1 is not applied to the work W, the position of the work W does not deviate from the predetermined position. Therefore, in order to return the work W tightly clamped by the clamping screw to the predetermined mounting position,
It is not necessary to loosen the clamping screw and then place the work W again.

The present invention is not limited to the above embodiments, but can be implemented in the following modes without departing from the spirit of the present invention. (1) As shown in FIG. 4, the inner bottom surface 2b of the ball housing portion 2
Is formed in a conical shape with a rounded tip, and its apex is supported by the contact ball 4. Therefore, the inner bottom surface 2b constitutes a support means for the contact ball 4. (2) Use a plurality of support balls 3. (3) The inner bottom surface 2b is formed in a hemispherical shape protruding toward the support ball 3 side. (4) A hemispherical support ball 3 that is a separate body from the inner bottom surface 2b is housed and arranged in the inner portion of the ball housing portion 2. (5) Change the material of the clamping screw body 1 from stainless steel material to, for example, iron or plastic. (6) Change the material of the contact balls 4 from stainless steel to iron, plastic, or the like. (7) In the above embodiment, the clamping screw body 1 has a hexagon socket set screw shape in which the wrench hole 1b is formed in the base end portion, but this is changed to, for example, a hexagon bolt or a hexagon socket bolt. To change.

[0019]

As described above, according to the clamping screw of the present invention, even if the work is firmly tightened, the main body of the clamping screw can be smoothly rotated at all times, and the contact between the ball and the work. No scratches on the surface. Moreover, since the rotational force of the clamping screw body is not applied to the work, the position of the work does not deviate from the predetermined position.

The above-mentioned excellent effects are exhibited.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment embodying a clamping screw of the present invention.

FIG. 2 is an enlarged sectional view showing a tip portion of a clamping screw.

FIG. 3 is a cutaway view showing a state where a work is fixed by a clamping screw.

FIG. 4 is a partially enlarged cross-sectional view showing another example.

FIG. 5 is a partially enlarged cross-sectional view showing a conventional clamping screw.

FIG. 6 is a partially enlarged cross-sectional view showing a conventional clamping screw.

[Explanation of symbols]

1 ... Clamping screw main body, 2 ... Ball housing,
3 ... Support balls constituting supporting means, 4 ... Contact balls as balls, L ... Rotation axis of clamping screw body, W ... Work, X ... One point on rotation axis of clamping screw body.

Claims (4)

[Claims] 1. A clamping screw body having a ball accommodating portion at its tip, a ball accommodated in the ball accommodating portion so as to be freely rotatable, and a part of which protrudes from the ball accommodating portion, and the ball. A clamping screw, which is provided in the accommodating portion and comprises a supporting means for supporting the ball at one point on the rotation axis of the clamping screw main body. 2. The clamping screw according to claim 1, wherein the supporting means is a curved surface formed to face the ball. 3. The clamping screw according to claim 1, wherein the supporting means is a convex portion formed to face the ball. 4. The clapping screw according to claim 1, wherein the support means is a support ball housed and arranged between a back portion of a ball housing portion and the ball.